Starbase101
How about drawing a drilling template on your computer at the appropriate size with holes marked in the correct locations, print it, cut to size, tape into position on the part, and mark/drill the holes? Or does the surface shape not accommodate such? Using some sort of removable template might help with setting the holes.

Treehugger
Hm, the template is an interesting idea. Only bad thing I can think of, is that, I suspect I will be needing a new template for most objects on the tank (I haven't checked this though).

I guess I could just, drill say 4-5-6 holes in a thin piece of styrene, and then very gently lay the overlay over the objects, but this probably would only work on flat objects, or around objects that have enough space for having a template thingy placed.

Treehugger
This takes a little practice to get good: ibb.co/FX2BKDY (replaced boltheads with boltheads + pin)

Some tips:
1) Spend some time figuring out if the existing bolts can be used as a guide for proper placement or not.
2) Use a Trumpeter chisel tool to cut off the old boltheads.
3) Spend some time marking the initial spot for each hole, using the tip of a sharp, and then rotate the blade a little for making the holes a little larger so that the drill bit is better centered into the hole-to-be-drilled.
4) Try to drill straight down, so that the bolt head rests horizontally on the plastic.
5) Better to stop if in doubt, and reevaluate, instead of just drilling out 10 holes just because you want to get finished.
6) It is a good idea to use a drillbit that is slightly smaller than required, such that the bolt pin gets a little stuck. That way you don't need any glue. If the hole is too large, any glue might seep onto the top side if applied on the bottom side. Optionally, because the bolts + pins are resin, you can add a drop of super glue on the bottom side to fix the bolts in place for good.

Also, don't pour all the tiny resin parts out of the bag and onto the table and then sneese, else you will find the tiny parts all over the place. 🙂

Also, make sure you use a soft material to press down any bolts, and not hard tools or your finger nail, as it will eventually deform the resin. A soft sanding stick is ok for adding some pressure to get the bolt + pin to get fully into place. If you press too hard, and the bolt has a washer, you will strip the washer as the bolt is forced down too far.

Treehugger
I just realized, if needing to fix a bolt head that aren't at the ideal position, then just cut it off, and glue on a separate bolt head without drilling any hole. 🙂

Danny Meer
It instant giving the model so much more detail, very nice 👍